Question #42234

1 Answer
Feb 18, 2018

29.8ml

Explanation:

Density of liquid oxygen = 1.141g/#cm^3#
Density of liquid hydrogen = 0.071 g/#cm^3#

Since 1ml=1#cm^3# and #density = (mass)/(volume)# we can calculate the masses of the above:
Mass oxygen#=1.141times10=11.41g#
Mass hydrogen= #0.071 times 50=3.55g#

We can calculate relative molecualr masses (I have used 1d.p. but you may wish to be more accurate)
#Mr (O_2)=16.0 times2=32.0#
#Mr (H_2)=1.0times2=2.0#

We can now work out the number of moles of each:
Moles #(O_2)=11.41/32.0=0.357 mol#

Moles #(H_2)=3.55/2.0=1.775 mol#

The reaction is
#2H_2 +O_2 to 2H_2O#

so 2 moles #H_2# reacts with 1 mole #O_2#
hence unreacted #H_2# = #1.775-(0.357times2)=1.061mol#

And so Mass = #1.061 times 2= 2.122g#

and volume = #2.122/0.071=29.9ml#